Sure Google has no legal obligation to send the traffic to the site, but it is still sort of dishonest. Google convices people to install AMP under the premise that it will help them. Instead, it just allows Google to monetize other people's content, at the expense of the creator.

It's hypocrital to bill AMP as an improved mobile experience, while sticking a big button at the top. Also hypocritical to penalize sites for scraped, dublicate content, while doing the same themselves.